Digital subtraction myelography is a useful adjunctive tool to conventional and CT myelography when spinal CSF leaks are present. In the case of a dorsal CSF leak, isolation of leakage sites may be enhanced when imaging is performed in the supine position. Injection of contrast through a lumbar drain instead of a spinal needle allows for supine positioning to detect dorsal CSF leaks.

From the manuscript

Supine Digital Subtraction Myelography for the Demonstration of a Dorsal Cerebrospinal Fluid Leak in a Patient with Spontaneous Intracranial Hypotension: A Technical Note

Abstract
A patient with spontaneous intracranial hypotension due to a spinal cerebrospinal fluid (CSF) leak required localization of the leakage site prior to surgical management. Conventional, computed tomography and prone digital subtraction myelography failed to localize the dural tear, which was postulated to be dorsally located. We present here a digital subtraction myelographic approach to accurately localize a dorsal site of CSF leakage by injecting iodinated contrast via a lumbar drain with the patient in the supine position.